With Covid-19 shots in billions of arms by now, evidence is emerging of how well they work in real-world settings. Vaccines authorized for emergency use have successfully subdued epidemics in nations where at least half of the population is fully immunized. But as more-transmissible variants spread, driving fresh outbreaks and an increase in breakthrough infections, health authorities are recommending some immunized individuals wear face-masks indoors to augment the protection of vaccines.
https://www.bloomberg.com/news/articles/2021-07-30/are-covid-shots-working-what-the-real-world-tells-us-quicktake?srnd=premium